Interferon has been shown to alter RNA metabolism by the induction of at least one endonuclease. Large changes in overall RNase activity are not normally induced by interferon. To extend these initial observations, we are looking at RNase and DNase activities in extracts derived from untreated and interferon treated cells using polynucleotide polyacrylamide activity gel electrophoresis. This system allows the detection and quantitation of individual activities rather than gross activity.